mod_ssl: Catch missing, mismatched or encrypted client cert/key pairs

with SSLProxyMachineCertificateFile/Path directives. PR 52212, PR 54698.
(check at startup, to prevent segfaults at proxy request time)

trunk patches: https://svn.apache.org/r1374214
               https://svn.apache.org/r1374216
               https://svn.apache.org/r1375445
               https://svn.apache.org/r1467593
2.4.x patch: https://people.apache.org/~kbrand/PR52212_54698_2.4.x.patch

Submitted by: kbrand
Reviewed by: jorton, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1476685 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -22,6 +22,10 @@ Changes with Apache 2.4.5
   *) mod_log_config: Fix crash when logging request end time for a failed
      request.  PR 54828 [Rainer Jung]
 
+  *) mod_ssl: Catch missing, mismatched or encrypted client cert/key pairs
+     with SSLProxyMachineCertificateFile/Path directives. PR 52212, PR 54698.
+     [Keith Burdis <keith burdis.org>, Joe Orton, Kaspar Brand]
+
   *) mod_ssl: Quiet FIPS mode weak keys disabled and FIPS not selected emits
      in the error log to debug level.  [William Rowe]
 

STATUS

@@ -90,16 +90,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
-   * mod_ssl: Catch missing, mismatched or encrypted client cert/key pairs
-    with SSLProxyMachineCertificateFile/Path directives. PR 52212, PR 54698.
-    (check at startup, to prevent segfaults at proxy request time)
-    trunk patches: https://svn.apache.org/r1374214
-                   https://svn.apache.org/r1374216
-                   https://svn.apache.org/r1375445
-                   https://svn.apache.org/r1467593
-    2.4.x patch: https://people.apache.org/~kbrand/PR52212_54698_2.4.x.patch
-    2.2.x patch: https://people.apache.org/~kbrand/PR52212_54698_2.2.x.patch
-    +1: kbrand, jorton, minfrin
 
 
 PATCHES PROPOSED TO BACKPORT FROM TRUNK:

modules/ssl/ssl_engine_init.c

@@ -1354,7 +1354,8 @@ static void ssl_init_proxy_certs(server_rec *s,
     for (n = 0; n < ncerts; n++) {
         X509_INFO *inf = sk_X509_INFO_value(sk, n);
 
-        if (!inf->x509 || !inf->x_pkey) {
+        if (!inf->x509 || !inf->x_pkey || !inf->x_pkey->dec_pkey ||
+            inf->enc_data) {
             sk_X509_INFO_free(sk);
             ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, s, APLOGNO(02252)
                          "incomplete client cert configured for SSL proxy "
@@ -1362,6 +1363,15 @@ static void ssl_init_proxy_certs(server_rec *s,
             ssl_die(s);
             return;
         }
+        
+        if (X509_check_private_key(inf->x509, inf->x_pkey->dec_pkey) != 1) {
+            ssl_log_xerror(SSLLOG_MARK, APLOG_STARTUP, 0, ptemp, s, inf->x509,
+                           APLOGNO(02326) "proxy client certificate and "
+                           "private key do not match");
+            ssl_log_ssl_error(SSLLOG_MARK, APLOG_ERR, s);
+            ssl_die(s);
+            return;
+        }
     }
 
     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02207)
@@ -1374,7 +1384,11 @@ static void ssl_init_proxy_certs(server_rec *s,
         return;
     }
 
-    /* Load all of the CA certs and construct a chain */
+    /* If SSLProxyMachineCertificateChainFile is configured, load all
+     * the CA certs and have OpenSSL attempt to construct a full chain
+     * from each configured end-entity cert up to a root.  This will
+     * allow selection of the correct cert given a list of root CA
+     * names in the certificate request from the server.  */
     pkp->ca_certs = (STACK_OF(X509) **) apr_pcalloc(p, ncerts * sizeof(sk));
     sctx = X509_STORE_CTX_new();